Stabilized floating bottom unit



June 9, 1959 N. w. EUREY 2,889,956

lsmmzran FLOATING BOTTOM UNIT Filed Dec. 6, 1955 v 2 Sheets-Sheet 1 N. W. EUREY STABILIZD FLOATING BOTTOM UNIT June 9, 1959 yF11-ed nec. s, 195s 2 Sheets-Sheet 2 wnmm- NoAH- W- EUQEV,

1NVENTOR.

ATTORNEY clude tilting thereof `pending application,

United States Pate 2,889,956 STABILIZED FLGATING BOTTOM UNIT Noah W'. Burley, Lincolnton, NJC., assignor, by mesne assignments, to Excel, Inc., Ln'colnton, NJC., a corporation of North Carolina' ApplicationDecember 6, 1955, Serial No, 551,379 I Claim. ((11.220-93) This invention relates to a self-contained false floating bottom unit for hand trucks and the like and, more espe- "cially, to a unit of this type having novel means incorporated therein for stabilizing the false: bottom to preupon the load being unevenly distributed.

False bottoms have heretofore been provided which are vertically movable in response to variations in weight placed' thereon so as to maintain the contents of a truck in which the false bottom is installed at a convenient elevation, but dii'culty has been experienced` in providing a practical and economically feasible bottom which will not bind or tilt upon the weight on the bottom being unevenly distributed.

The present invention is an improvement over my co- Serial Number 347,097', filed April 6, 1953, and entitled Bobbin Truck` with False 'Movable Bottom, now Patent No. 2,769,568, granted November 6, 1956.

It is an object of this'invention to provide a stabilized self-contained false floating bottom unit which includes an extremely simple mechanism wherein the number of moving parts has been held to anv absolute minimum.

It is another object of this invention to provide a stabilized false floating bottom which will enable the contents of a truck, in which the bottom of the present invention is disposed, to be maintained' at a convenient elevation at all times regardless of the distribution of the weight on the bottom.

It is another object of this invention to provide a stabilizedffalseY floating bottom as a self-contained unit which may be manufactured independently of the truck and which may subsequently be readily installed in an existing' truck without the necessity of employing anyV type of fastening means,`the movable false bottom of this invention being satisfactorily mounted inY the truck by merely placingv the frame thereof onV the existing truck bed.

More specifically, it is an object of this invention to provide 'a novel stabilizing mechanism ini combination with afalse floating bottom wherein said stabilizing mechanism comprises a pluralityY of levers pivotally interconnected adjacent' corresponding ends and extending between a base'and the medial portion of the platform of said false movable'bottom, and stabilizing links pivotally connecting the medial portions ofy some of said levers to the endsof others of said levers to limit relative movement between the levers whereby vertical movement of one partof said platform will result in` corresponding movement of the remainder of the platform.

Another object of this' invention is to provide a novel stabilizing mechanism comprised of two groups of levers wherein-the levers of each group are pivotally connected at corresponding ends to deiine upper and lower pairs of angularly disposed levers in each group. The upper ends of the upper pair of levers are pivotally connected to a movableplatform or bed and thee lower-ends of the lower pair of-.levers are pivotally connected to a base or supporting -member.

The levers which comprise each pair v are not connected to each other at their medial portion but the end of one lever in each pair is connected `adjacent the medial portion of the other lever in that pair whereby movement of the levers in each group in response to depression of the platform is limited tooutward movement of the junctures of the upper and lower pairs of levers in each group relative to each other. This arrangement eliminates the friction which has heretofore been occasioned by the use of slidable connections between the platform and linkage.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings,` in which Figure 1 is a plan view of the improved false floating bottom unit disposed within a hand truck;

Figure 2 is an enlarged fragmentary longitudinal sectional view taken substantially along the line 2--2 in Figure l and showing the platform of the false bottom and its stabilizing mechanism in raised position;

Figure 3 is an enlarged fragmentary transverse sectionall view through a portion of the false bottom and truck, omitting the wheels, and showing the false bottom' and stabilizing mechanism in raised position;

Figure 4 is an enlarged longitudinal sectional view, with parts broken away, taken substantially along the line 4 4 in Figure l and showing the platform of the false bottom and its stabilizing mechanism in lowered or retracted position;

Figure 5 is a fragmentary inverted plan view taken substantially along the -line 5--5 in Figure 4.

Referring more specifically to the drawings, the numeral 10 broadly designates a hand truck comprising side lwalls 11 and 12 and end walls 13 and 14 mounted upon a base 15 vwhich may lcomprise either a planar member or an open framework from which depend a plurality of wheels 16 suitably journaled in brackets i7.

The stabilized false bottom of the present invention is particularly adapted to be associated lwith a structure of this type, and although the simplified Structure of the stabilized false bottom readily lends itself to'being manufactured as a self-contained unit for subsequent association with a hand truck, it is to be understood that it may be incorporated into the frame of such a hand truck without departing from the spirit of the invention. In this manner, the expense of a complete bottom or base l5 of the truck i@ may be eliminated.

The stabilized false bottom mechanism comprises. a pair of longitudinally extending base or supporting-members which are shown in the form of angle irons 20 and 2l which are adapted to rest upon the bottom 15 and serve to support the false bottom unit. Thebase members Ztl and 2i are interconnected by transversely extendingframe members 22 and 23 disposed adjacent opposit'e ends of the base members 20"and 21, said frame members 22, 23 preferably being of sufcient width to serve asy seats for springs 24 and 25 which extend upwardly therefrom. The frame members 22 and 2?v are alsoV preferably provided with flanges 26 and 27 for the purposes of rigidity and also to aid in maintaining the springs Z4, 25 on their respective seats.

The ends ofthe springs-24, 25 remote from the base members '20, 2l are fastened by brakets 28 to respective plates 29, 30 which lare secured by bolts orrivets 3l to the undersurface of a bed or false bottom platform 32. 'The bed 32is`provi'ded with a downturneil peripheral ange 33, preferably provided with openings 34 Yadjacent the'corners` thereof I through which antifr'iction rollers 35 project to' engage the end walls 13 and 14 tol facilitatevertical Vmovement ofthe bed 332 within the confines of the truckl;

The springs 24 and 2,5 impart vertical movementto the bed 32 within the contines of the truck 10 in response to variations in weight placed upon the bed 32. The resiliency of the springs 24, 25 may be adjusted as desired to cause the bed 32 to be depressed upon a predetermined amount of weight being placed thereon and Yto likewise cause the bed 32 to be elevated as the` weight thereon is decreased a predetermined amount.

The principal feature f the present invention resides in a novel stabilizing mechanism which extends between the bed 32 and the base members 20, 2l whereby undesirable tilting of the bed 32 from a predetermined plane is eliminated even though the weight on the bed is unevenly distributed.

The stabilizing mechanism includes a pair of linkage systems 40 and 40', the linkage system 40 extending between the base member 20 and the bed 32 and the linkage system 40 extending between the base member 21 and the bed 32. These linkage systems are interconnected to prevent relative movement therebetween and are constructed in an identical fashion so that, for purposes of illustration, only the linkage system 40 will be described in detail, it being understood that like parts of the linkage system 40 will bear like reference numerals with the prime notation added.

'Ihe linkage system 40 includes upwardly converging levers 44 and 45 which are pivotally connected adjacent their lower ends to the supporting members 20 as by pivot pins 41. The pivot pins 41 loosely penetrate their respective levers 44, 45 an'd the supporting member 20, and are rigidly secured to corresponding end portions of transverse bracing members 42 and 43. The bracing members 42 and 43 extend between the lower end portions of respective levers 44, 44 and 45, 45' and are rigidly secured thereto so that movement of the levers l44, 45 will necessarily result in corresponding movement of levers 44', 45'.

The levers 44, 45 converge upwardly from their respective pivot pins 41 `and cross each other adjacent their medial portions which are unconnected so that the levers 44, 45 are -free to move relative to each other as the bed 32 is elevated or depressed (Figures 2 and 4) 'I'he upper ends of links 44, 45 are pivotally connected to the lower ends of levers 50 and 51 as by respective pivot pins 46 and 47. The levers 50 and 51 converge upwardly from the respective pivot pins 46 and 47 and cross each other adjacent their medial portions which are unconnected so that the levers 50, 51 are also free to move relative to each other as are levers 44 and 45. The pivot pin's 46, 47 extend transversely and also serve to pivotally connect respective links 44',50 and 45', 51 as shown in Figure 3.

A stabilizing link 52 is pivotally connected at one end to the pivot pin 47 and at its other end to the lower end portion of the lever 44 as by a pivot pin 53. Another stabilizing link 54 is pivotally connected at one end to the pivot pin 47, the other end of the stabilizing link 54 being pivotally connected as by a pivot pin 55 'to the upper end portion of the link 51.

The levers 51 and 51 are rigidly interconnected by ,a transverse bar 56 which extends therebetween and it will be observed in the drawings that the levers 51 and r51 .are disposed inwardly of the levers 50 and 50 so that the bar 56 will not interfere with movement of the levers relative to each other. Likewise, the stabilizing links 52, 54 are disposed inwardly of the inner levers 44 and 51.

The upper ends of the levers 50 and 51 are pivotally and slidably connected to a longitudinally extending angle bar 61 as by pivot'pins 62 which loosely penetrate slots 63 in the vertical flange of the angle bar 61. The slots 63 terminate in short distance from the ends of the angle bar 61 and communicate With the ends thereof but are preferably closed by transverse angle bars 64 and 65 which are secured to the ends of the angle bars Cil 61, 61. The transversely extending pivot pins 62 are connected by a longitudinally extending link 67 which is loosely penetrated adjacent opposite ends by the pins 62, and which link 67 is provided witlzty a closed longitudinal slot 68 through which one of the pins 62 passes to permit limited outward movement of the pins 62 relative to each other.

The horizontal anges of the angle bars 64 and 65 are secured to the bed 32 as by rivets or bolts 66 and suitable rollers 70 are journaled on the pins 62 to facilitate limited longitudinal movement of the stabilizing mechanisrn relative to the bed or platform 32. As most clearly seen in Figure 3, the horizontal anges of the angle bars 61, 61 serve as trackways for the rollers 70 which may be confined against axial movement relative to their respective pins 62 as by stops 71.

Method of operation It will be appreciated from the foregoing description that the stabilizing mechanism has a minimum of moving parts which are actuated with a minimum of frictional contact, thereby permitting more positive and accurate control of the platform 32 during yits vertical movement.

It will be observed in Figures 2 and 4 that the pivot pin 46 is disposed at a higher elevation than the pivot piu 47. It will be further observed in Figures 2 and 4 -that this -is true despite the fact that all of the levers 44, 45, 50, 51 and 44', 45', 50 and 51 are of equal length, as are the stabilizing links 52, 52 and 54, 54.

The elevation of the pivot pin 46 is iixed by the location of the pivot pin 41 and the length of the link 52 the pivot pin 41 serving to tix the lower end of the lever 44 relative to the longitudinal basemember 21 and the length of link 52 serving to x the angularity of the lever 44 and the elevation of the upper end thereof relative to the elevation of the upper end of lever 45.

'I'he length of the links 52, 54 and their location relative to the levers to which they are connected is such as to prevent the links 52, 54 from assuming either a vertical or a horizontal attitude with the result that the upper end of the link 52 and the lower end of link 54 deiine an arc of less than degrees as the platform 32 passes from its extended position to its retracted position. Consequently it is impossible for the links to bind.

The fact that the pivot pin 46 is disposed at a higher elevation than the pivot pin 47 tends to impart movement to the platform 32 toward the end wall 14 as the platform is depressed. However, it will be observed that the platform is wedged between end walls 14 and 13 by rollers 35 which engage the inner surfaces thereof. The slot 63 in link 67 and the slot 68 in link 67 are provided in order to overcome this tendency of the platform to move toward end wall 14 as it is depressed, said slots permitting the levers 50, 51 connected thereto by pivot pins 62 to have limited longitudinal movement relative to the platform 32 as it is raised and lowered.

It will be observed in Figure 2 that the pin 62 which connects lever 50 to slot 63 is disposed in the medial portion of the slot when the platform 32 is in raised position. As the platform is lowered the pin 62 connected to lever 50 moves to the right end of slots 63 and 68 in the drawings (Figure 4). Conversely, as platform 32 is raised the pin 62 connected to lever 50 returns to its original position (Figure 2).

Assuming a weight is applied to platform 32 adjacent end wall 14 to cause downward movement of the bed 32 from the position shown in Figure 2, the lever 51 will be depressed and the stabilizing link 54 will simultaneously cause depression of the pivot pin 46 thereby causing a like depression of the lever 50. Of course, as the pivot pin 46 is depressed the lever 44 will likewise be depressed and the stabilizing link 52 will cause simultaneous depression of the lever 45 whereby all moving parts of linkage 40 will be simultaneously moved downwardly to insure constant and uniform depression of the bed 32.

It is thus seen that there is provided an improved stabilizing mechanism for false movable bottoms which will maintain the bed of the false bottom in a constant plane regardless of the distribution of weight thereon.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being dened in the claim.

I claim:

In a hand truck having a .bottom and walls and also having a false movable bottom mechanism including a bed disposed in variable spaced planar relation above the base of said truck and resilient means normally urging said bed away from the base of the truck, an improved stabilizing mechanism for preventing tilting of the bed despite uneven distribution of Weight thereon, said stabilizing mechanism including a pair of longitudinally extending support members disposed adjacent opposite side edges of the base of the truck, rst and second groups of pivotally interconnected levers each extending between one of said support members and the bed, each group of levers including rst and second levers, means pivotally connecting the lower ends of said first and second levers to spaced points of their respective support members and said means also confining the lower ends of the rst and second levers against movement other than pivotal movement relative to their respective support members, the first and second levers converging upwardly from their respective pivotal connections with the support members and crossing each other adjacent their medial portions, each group of levers also including third and fourth levers, means connecting corresponding ends of the third and fourth levers to the bed for pivotal and limited longitudinal movement relative to the bed', said third and fourth levers converging downwardly from their respective connections with the bed and crossing each other adjacent their medial portions, means pivotally connecting the upper end of the rst lever to the lower end of the third lever and means pivotally connecting the upper end of the second lever to the lower end of the fourth lever, a first stabilizing link pivotally connected to said first-named pivot means, said rst stabilizing link extending from the pivotal juncture of the rst and third levers to a point on the upper end portion of the fourth lever and being pivotally connected thereto, a second stabilizing link pivotally connected to said last-named pivot means, said second stabilizing link extending from the pivotal juncture of the second and fourth levers to a point on the lower end portion of the rst Ilever and being pivotally connected thereto, and said stabilizing links being so connected to their respective levers as to maintain the rst and second named pivot means in different planes parallel to the base whereby the bed is stabilized against tilting under an unevenly distributed load.

References Cited in the file of this patent UNITED STATES PATENTS 1,632,270 Bradley et al. June 14, 1927 2,156,148 DiGiacomo et al Apr. 25, 1939 2,449,892 Gibbs Sept. 21, 1948 2,556,207 Mueller .Tune 12, 1951 2,692,177 Larsen Oct. 19, 1954 

